U.S. patent application number 11/972793 was filed with the patent office on 2009-07-16 for solder contacts and methods of forming same.
Invention is credited to Martin Franosch, Barbara Hasler, Alfred Martin, Klaus-Guenter Oppermann.
Application Number | 20090179333 11/972793 |
Document ID | / |
Family ID | 40786014 |
Filed Date | 2009-07-16 |
United States Patent
Application |
20090179333 |
Kind Code |
A1 |
Martin; Alfred ; et
al. |
July 16, 2009 |
SOLDER CONTACTS AND METHODS OF FORMING SAME
Abstract
An integrated circuit that comprises a substrate and a
structured layer on the substrate. The structured layer comprises
an opening to the substrate, a first field and a second field on
the substrate, wherein the first field and the second field, at
least in part, overlap with the opening. The integrated circuit
further comprises a first material in the area of the first field
and a second material in the area of the second field. The first
material impedes a wetting by a solder material, and the second
provides a wetting by the solder material.
Inventors: |
Martin; Alfred; (Munich,
DE) ; Hasler; Barbara; (Munich, DE) ;
Franosch; Martin; (Munich, DE) ; Oppermann;
Klaus-Guenter; (Holzkirchen, DE) |
Correspondence
Address: |
PATTERSON & SHERIDAN, LLP;Gero McClellan / Qimonda
3040 POST OAK BLVD.,, SUITE 1500
HOUSTON
TX
77056
US
|
Family ID: |
40786014 |
Appl. No.: |
11/972793 |
Filed: |
January 11, 2008 |
Current U.S.
Class: |
257/779 ;
257/E23.023; 438/612 |
Current CPC
Class: |
H01L 24/13 20130101;
H01L 2224/11013 20130101; H01L 24/81 20130101; H01L 2924/01068
20130101; H01L 2924/19041 20130101; H01L 24/11 20130101; H01L
2924/01013 20130101; H01L 2924/1434 20130101; H05K 2201/0989
20130101; H01L 24/05 20130101; H01L 24/06 20130101; H01L 2924/01079
20130101; H01L 2224/13006 20130101; H01L 2924/01067 20130101; H01L
2224/05647 20130101; H01L 2224/05569 20130101; H01L 2924/1436
20130101; H01L 2224/11849 20130101; H05K 2203/043 20130101; H01L
2224/11422 20130101; H01L 2224/8109 20130101; H01L 2924/01032
20130101; H01L 2224/11334 20130101; H01L 2924/01078 20130101; H05K
3/3485 20200801; H01L 2924/01029 20130101; H01L 2924/0103 20130101;
H05K 3/3452 20130101; H01L 2224/05655 20130101; H01L 2224/16145
20130101; H01L 2924/01004 20130101; H05K 2201/2081 20130101; H01L
2224/05611 20130101; H01L 2224/81205 20130101; H01L 2924/01082
20130101; H01L 2224/81815 20130101; H01L 2924/01033 20130101; H01L
2224/13012 20130101; H01L 2924/01047 20130101; H01L 2924/014
20130101; H01L 2224/131 20130101; H01L 2924/19042 20130101; H01L
2224/05613 20130101; H01L 2224/10125 20130101; H01L 2224/05644
20130101; H01L 2224/10145 20130101; H01L 2224/03828 20130101; H01L
2224/0401 20130101; H01L 2224/0557 20130101; H01L 2224/13014
20130101; H01L 2924/19043 20130101; H01L 2924/01006 20130101; H01L
24/16 20130101; H01L 2224/06136 20130101; H01L 2224/11332 20130101;
H01L 2224/16227 20130101; H01L 2224/16225 20130101; H01L 2224/8123
20130101; H01L 2224/1181 20130101; H01L 2224/05616 20130101; H01L
2224/05639 20130101; H01L 2924/0002 20130101; H01L 2924/14
20130101; H01L 2924/01005 20130101; H01L 2924/1432 20130101; H01L
2224/05624 20130101; H01L 2224/11622 20130101; H01L 2224/131
20130101; H01L 2924/014 20130101; H01L 2224/13014 20130101; H01L
2924/00014 20130101; H01L 2924/0002 20130101; H01L 2224/05552
20130101; H01L 2224/81205 20130101; H01L 2924/00014 20130101 |
Class at
Publication: |
257/779 ;
438/612; 257/E23.023 |
International
Class: |
H01L 23/48 20060101
H01L023/48; H01L 21/44 20060101 H01L021/44 |
Claims
1. A method of forming a solder contact to a substrate, the method
comprising: providing a first field on a surface of the substrate,
wherein the first field impedes a wetting by a solder material;
providing a second field on the surface of the substrate, wherein
the second field is wettable by the solder material; providing a
structured layer on the surface, wherein the structured layer
comprises an opening to the substrate, and wherein the opening, at
least in part, exposes both the first field and the second field;
filling the opening with the solder material, whereby the solder
material is brought into contact with the first field and the
second field; and liquefying the solder material, whereby the
solder material is pulled from the first field, and a portion of
the solder material is caused to protrude from the opening, wherein
the portion of the solder material forms the solder contact.
2. The method as claimed in claim 1, wherein providing the second
field comprises a providing of a metallization pad on the surface
of the substrate.
3. The method as claimed in claim 1, wherein filling the opening
with the solder material comprises: providing a first pressure in
the opening; providing a liquefied solder material to an aperture
of the opening; and providing a second pressure to the liquefied
solder material, wherein the second pressure is greater than the
first pressure, thereby filling the opening with the solder
material.
4. The method as claimed in claim 1, wherein the opening is filled
with any solder material of the group of a liquid solder material,
a liquefied solder material, a granular solder material, a
powder-like solder material, and a paste-like solder material.
5. The method as claimed in claim 1, wherein providing the
structured layer comprises: providing a photo resist layer;
exposing the photo resist layer to masked radiation; and removing a
part of the photo resist layer in an area of the opening, thereby
forming the structured layer.
6. The method as claimed in claim 1, wherein the portion of the
solder material caused to protrude from the opening is solidified,
thereby forming a solder ball.
7. The method as claimed in claim 1, wherein the portion of the
solder material caused to protrude from the opening is soldered to
a contact pad of any of the group of a circuit board, a printed
circuit board, a mother board, a module board, and a chip carrier,
thereby forming a solder contact from the substrate to the contact
pad.
8. The method as claimed in claim 1, wherein the method further
comprises a removing of an oxide on the solder material after the
filling of the opening with the solder material.
9. A method of fabricating an integrated circuit, the method
comprising: providing a substrate, wherein the substrate comprises
a functional circuit; providing metallization pads on a surface of
the substrate, wherein the metallization pads are coupled to the
functional circuit; providing a structured layer on the surface,
wherein the structured layer comprises an opening, wherein the
opening exposes, at least in part, both the metallization pad and
the surface of the substrate; filling the opening with a solder
material, whereby the solder material is brought into contact with
the first field and the second field; and liquefying the solder
material, whereby the solder material is pulled from the surface of
the substrate in the opening and a portion of the solder material
is caused to protrude from the opening, the portion of the solder
material forming a solder ball.
10. The method as claimed in claim 9, wherein filling the opening
with the solder material further comprises: providing a bath of a
liquid solder material; providing a first pressure in the opening
of the structured layer and atop the bath; dipping the structured
layer with the substrate into the bath, thereby covering an
aperture of the opening with the bath; providing a second pressure
to the bath, wherein the second pressure is greater than the first
pressure, thereby filling the opening with the solder material; and
retracting the substrate with the structured layer from the
bath.
11. The method as claimed in claim 10, wherein the substrate and
the structured layer is cooled after retracting from the bath,
thereby solidifying the solder material in the opening.
12. An integrated circuit, comprising: a substrate; a structured
layer on the substrate, wherein the structured layer comprises an
opening to the substrate; a first field and a second field on the
substrate, wherein the first field and the second field, at least
in part, are exposed by the opening; a first material in the area
of the first field, wherein the first material impedes a wetting by
a solder material; and a second material in the area of the second
field, wherein the second material is wettable by the solder
material.
13. The integrated circuit as claimed in claim 12, wherein the
first field has a length along a direction to the second field in
any range of the group of a range of 1 micron to 10 microns, a
range of 10 microns to 100 microns, and a range of 100 microns to
1000 microns.
14. The integrated circuit as claimed in claim 12, wherein the
second field is a round field with a diameter in any range of the
group of a range of 1 micron to 10 microns, a range of 10 microns
to 100 microns, and a range of 100 microns to 1000 microns.
15. The integrated circuit as claimed in claim 12, wherein the
second field is a rectangular field with a side width in any range
of the group of a range of 1 micron to 10 microns, a range of 10
microns to 100 microns, and a range of 100 microns to 1000
microns.
16. The integrated circuit as claimed in claim 12, wherein the
first field surrounds the second field.
17. The integrated circuit as claimed in claim 12, wherein the
first field is arranged radially to the second field.
18. The integrated circuit as claimed in claim 12, wherein the
first field is arranged tangentially to the second field.
19. The integrated circuit as claimed in claim 12, wherein a
fraction of a surface of the substrate is exposed to the opening in
the area of the first field.
20. The integrated circuit as claimed in claim 12, wherein a
metallization pad is arranged on the substrate in the area of the
second field.
21. The integrated circuit as claimed in claim 12, wherein a second
partial opening of the opening above the second field is filled
with a solder material, and wherein a first partial opening of the
opening above the first field is devoid of the solder material.
22. The integrated circuit as claimed in claim 21, wherein a
portion of the solder material is arranged on a surface of the
structured layer, and wherein the portion forms a continuous solder
material with the solder material in the second partial
opening.
23. The integrated circuit as claimed in claim 12, wherein the
structured layer comprises trenches to the substrate, wherein the
trenches create islands of the structured layer, and wherein the
opening is arranged on an island of the structured layer.
24. A circuit system, comprising: a substrate, wherein the
substrate comprises an integrated circuit; a metallization pad on a
surface of the substrate; a structured layer on the substrate,
wherein the structured layer comprises an opening, wherein the
opening exposes, at least in part, both the metallization pad and
the substrate surface; a circuit board, wherein the circuit board
comprises a contact pad that faces the opening of the structured
layer; and a solder contact, wherein the solder contact partially
fills the opening above the metallization pad, and wherein the
solder contact is coupled to the metallization pad and the contact
pad.
25. The circuit system as claimed in claim 24, wherein the
integrated circuit comprises a memory circuit, and wherein the
circuit board comprises a memory module board.
Description
BACKGROUND OF THE INVENTION
[0001] The invention relates to integrated circuit and circuit
system manufacturing methods and structures, and more particularly
to methods of forming electrical and mechanical connections for an
integrated circuit and circuit system.
BRIEF DESCRIPTION OF THE DRAWINGS
[0002] So that the manner in which the above recited features of
the present invention can be understood in detail, a more
particular description of the invention, briefly summarized above,
may be had by reference to embodiments, some of which are
illustrated in the appended drawings. It is to be noted, however,
that the appended drawings illustrate only typical embodiments of
this invention and are therefore not to be considered limiting of
its scope, for the invention may admit to other equally effective
embodiments.
[0003] FIGS. 1A through 1C show an integrated circuit in various
stages during manufacturing according to one embodiment;
[0004] FIGS. 2A through 2C show an integrated circuit in various
stages during manufacturing according to another embodiment;
[0005] FIGS. 3A through 3C show a solder contact in various stages
during manufacturing according to a further embodiment;
[0006] FIGS. 4A through 4C show a solder contact in various stages
during manufacturing according to a further embodiment;
[0007] FIGS. 5A through 5C show a solder contact in various stages
during manufacturing according to a further embodiment;
[0008] FIGS. 6A through 6C show a solder contact in various stages
during manufacturing according to a further embodiment;
[0009] FIGS. 7A through 7C show a solder contact in various stages
during manufacturing according to a further embodiment;
[0010] FIGS. 8A through 8C show a solder contact in various stages
during manufacturing according to a further embodiment;
[0011] FIG. 9 shows a schematic side view of an integrated circuit
according to another embodiment;
[0012] FIG. 10 shows a schematic side view of an integrated circuit
according to another embodiment;
[0013] FIGS. 11A through 11F show schematic views of a solder
contact being formed on a substrate, in various stages during
manufacturing, according to another embodiment;
[0014] FIGS. 12A and 12B show schematic views of an integrated
circuit in conjunction with a circuit board according to another
embodiment;
[0015] FIGS. 13A and 13B show schematic views of an integrated
circuit in conjunction with a circuit board according to another
embodiment;
[0016] FIG. 14 shows a schematic top view of a fraction of an
integrated circuit according to yet another embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0017] Various implementations of the present invention may provide
particular advantages for an improved method of forming a solder
contact, an improved method of fabricating an integrated circuit,
an improved integrated circuit, and an improved circuit system.
[0018] The recited features will become clear from the following
description of implementations of the present invention, taken in
conjunction with the accompanying drawings. It is to be noted,
however, that the accompanying drawings illustrate only typical
implementations of the present invention, and are, therefore, not
to be considered limiting of the scope of the invention. The
present invention may admit equally effective implementations.
[0019] FIGS. 1A through 1C show an integrated circuit in various
stages during manufacturing according to one embodiment.
Accordingly, a solder contact is being formed to an integrated
circuit. As shown in FIG. 1A, an integrated circuit 10 comprises a
structured layer 200 and a substrate 100. The structured layer 200,
comprising an opening 3000, is arranged on a substrate surface 1001
of the substrate 100. The opening 3000, which exposes a part of the
substrate surface 1001 may comprise a uniform cross-section along
its depth, such that a part of the substrate surface 1001, this
part being exposed by the opening 3000 and forming a ground face of
the opening 3000, and an aperture 3001 of the opening 3000 at a
layer surface 2001 of the structured layer 200 all possess a shape
corresponding to the uniform cross-section.
[0020] The ground face may comprise a first field 1011 and a second
field 1012, which may be fractions of the ground face and/or the
substrate surface 1001. Both the first field 1011 and the second
field 1012 may extend along the substrate surface 1001 between the
substrate 100 and the structured layer 200. In one embodiment, the
material of the substrate 100 in the area of the first field 1011
impedes the wetting by a solder material. Impeding the wetting by a
solder material may comprise a property such that the respective
material does not mix, solve, or form a solder connection to a
solder material. In contrast to that, the material of the substrate
100 in the area of the second field 1012 does provide wetting to a
solder material. Providing wetting to a solder material may
comprise a property, that the respective material may solve, at
least in part, in a liquid solder material or that it may form a
solder connection with the solder material. Such wetting to a
solder material may be provided by a metallization pad, a
metallized area, a doping of the substrate 100, at least in the
area of the second field 1012, and/or a specific treatment of the
respective part of the substrate 100.
[0021] The opening 3000 may furthermore comprise a first partial
opening 3100 and a second partial opening 3200. The first partial
opening 3100 may be defined as a partial volume of the opening 3000
being located above the first field 1011 of the substrate surface
1001, whereas the second partial opening 3200 may be defined as a
partial volume of the opening 3000 being located above the second
field 1012 of the substrate surface 1001. The first partial opening
3100 and the second partial opening 3200 may form in conjunction
the opening 3000.
[0022] The substrate 100 may comprise a semiconductor substrate,
which, in turn, may comprise electronic, optical, and/or other
functional elements. Such elements may comprise transistors,
resistors, conductors, capacitors, inductors, diodes, emitters,
sensors, insulators, lasers, and/or other entities as they are
known from the manufacturing of integrated devices. For example,
the substrate 100 may comprise a silicon substrate with an
integrated circuit. Such integrated circuits may include a
flip-chip, a memory circuit, a dynamic random access memory (DRAM)
circuit, a memory controlling circuit, a central processing unit
(CPU) circuit, a signal processing circuit, a logical circuit, an
electronic signal processing circuit and/or an optical signal
processing circuit. Furthermore, the substrate 100 may comprise
more than one single substrate, i.e., a stack of individual and/or
identical substrates. Furthermore, the substrate 100 may form a
part or be a substrate of a substrate stack. Such a stack may
comprise one or more identical substrates which are stacked, for
example, in order to enhance a memory capacity, enhance a
processing power, and/or distribute tasks to several sub-circuits
of the integrated circuit.
[0023] The structured layer 200 may comprise a polymer, a photo
resist, an SU8-photo resist, an oxide, silica, a solder stop paste,
a passivation layer, and/or a material that impedes a wetting by a
solder material. The openings 3000 in the structured layer 200 may
be provided by means of photolithography, lithography, electron
beam lithography, anisotropic etching, reactive ion etching,
exposure to masked radiation, and/or other related techniques as
they are known from the manufacturing of integrated devices.
[0024] In a subsequent process stage, the opening 3000 of the
structured layer 200 may be filled with a solder material 400, as
shown in FIG. 1B. The filling of the opening 3000 with the solder
material 400 may be effected by means of a method as being
described in conjunction with embodiments described herein. In this
stage, a surface 4001 of the solder material 400 in the area of the
layer surface 2001 may possess a curvature, such as a concave or
convex curvature.
[0025] In a subsequent process stage, a part of the solder material
400 is ejected from the opening 3000 of the structured layer 200
(i.e. a portion of the solder material 400 protrudes from the
opening 300), thereby forming a solder contact 600, as shown in
FIG. 1C. The solder contact 600 may extend from the layer surface
2001 of the structured layer 200, and may, in this case, comprise a
solder ball. Such a projecting solder contact 600 may subsequently
be soldered, for example, to a module board, to a mother board, to
a chip carrier, to a respective contact pad of a circuit board, or,
in general, to any other circuit. In this way, a solder contact may
be established to the integrated circuit 10 from any external
circuitry.
[0026] In one embodiment, the solder material 400 is arranged in
the opening 3000 and above it in such a way, that it forms a
physical contact to the second field 1012, whereas the solder
material 400 is separated from the first field 1011 for the largest
part of the first field 1011. The largest part of the first field
1011 may be defined in a way that the fractional area of the first
field 1011 which is still covered by the solder material 400 is
less than the fractional area of the second field 1012 which has
contact to the solder material 400. A fraction of solder material
400 that may be arranged in the first partial opening 3100 during
preceding process stages, as they have been described in
conjunction with FIGS. 1A and 1B, may now provide solder material
400 for the projecting solder contact 600. An ejection from the
respective solder material 400 from the first partial opening 3100
may now form, at least in part, the solder contact 600. The first
partial opening 3100 may, in this state, remain empty for most of
its part, i.e., more solder material 400 is arranged in the second
partial opening 3200 than in the first partial opening 3100.
[0027] FIGS. 2A through 2C show an integrated circuit in various
stages during manufacturing according to another embodiment.
Accordingly, an integrated circuit 20 comprises the structured
layer 200 and the substrate 100. The structured layer 200,
comprising the opening 3000, is arranged on the substrate surface
1001. The opening 3000, exposes a part of the substrate surface
1001 in the area of the first field 1011.
[0028] In one embodiment, there may be arranged a metallization pad
500 on the substrate 100 in the area of the second field 1012.
Whereas, the material in the area of the first field 1011 impedes a
wetting by a solder material, the material and/or the surface of
the metallization pad 500 may provide a wetting to a solder
material. The metallization pad 500 may cover a part of the ground
face of the opening 3000 and/or may extend on the substrate 100
between the substrate 100 and the structured layer 200. The
metallization pad 500 may comprise a solderable material, such as
nickel, nickel/gold, tin, lead, copper, silver, bismuth, aluminum,
gold, or an alloy thereof. Furthermore, the metallization pad 500
may comprise a flux, such as collophony, urea, zinc chloride,
and/or related flux materials. The metallization pad 500 may
furthermore be provided as a an interface of a metal entity that
may be buried in the substrate 100, such as an outer face of a
metal signal line, a metallized via, or a cavity of the substrate
100 being filled with a respective metal.
[0029] Furthermore, at least a part of the ground face of the
opening 3000 may not be covered by the metallization pad 500, and
may, therefore, provide different wetting properties. The material
of the substrate 100 and/or the material at the substrate surface
1001 may impede the wetting by a solder material. Furthermore, a
solder stop material may be arranged on the substrate 100 in the
area of the first field 1011.
[0030] In a subsequent process stage, the opening 3000 of the
structured layer 200 may be filled with a solder material 400, as
shown in FIG. 2B. The filling of the opening 3000 with the solder
material 400 may be effected by means of a method as being
described in conjunction with embodiments described herein.
[0031] In a subsequent process stage, a part of the solder material
400 may be ejected from the opening 3000 of the structured layer
200, thereby forming the solder contact 600, as shown in FIG. 2C.
In one embodiment, the solder material 400 may be arranged in the
opening 3000 and above it in such a way, that it forms a physical
contact to the metallization pad 500, to which it may form a direct
solder connection. The solder material 400 is separated from the
first field 1011. The first partial opening 3100 may, in this
state, remain empty for most of its part, i.e., more solder
material 400 is arranged in the second partial opening 3200
adjacent to the metallization pad 500 than in the first partial
opening 3100. The solder material 400 may also be accumulated above
the metallization pad 500, which wets the solder material 400.
Therefore, solder material 400 may be contracted above the
metallization pad 500 and may be expelled from the partial opening
3100, in which the solder material 500 is a facing material and/or
surfaces which impedes the wetting by the solder material 400.
Hence, the projecting solder contact 600 may be formed by means of
the accumulation of the solder material 400 above the metallization
pad 500.
[0032] FIGS. 3A through 3C show a solder contact in various stages
during manufacturing according to a further embodiment. FIG. 3A
shows a schematic top view of a first partial opening 3101 and a
second partial opening 3201 in a structured layer 201 on the
substrate 100. The first partial opening 3101 above a first field
1111 of the substrate surface 1001 (as shown in FIGS. 3B and 3C)
and the second partial opening 3201 above a second field 1112 of
the substrate surface 1001 (as shown in FIGS. 3B and 3C) form a
continuous opening in the structured layer 201. A metallization pad
501 is arranged on the substrate 100 in the area of the second
field 1112, which may provide a wetting to a solder material. The
material and/or the surface of the substrate 100 in the area of the
first field 1111 impede the wetting by a solder material.
[0033] In one embodiment, the first field 1111 comprises a
rectangular shape and the first partial opening 3101 may comprise a
rectangular cross-section. An aspect ratio, being defined as the
ratio of the length of the respective rectangular area divided by
the width of the respective rectangular area, may be above 1, may
be above 2, or may be above 5. The length of the respective
rectangular area may be in a range of 1 to 10 microns, may be in a
range of 10 to 100 microns, or may be in a range of 100 to 1000
microns. In addition to this, the second field 1112 may comprise a
round shape and the second partial opening 3201 a round
cross-section. Round geometries may include oval, circular, and/or
a curvatured cross-section and shape. A median diameter of the
respective round area may be in a range of 1 to 10 microns, may be
in a range of 10 to 100 microns, or may be in a range of 100 to
1000 microns.
[0034] FIG. 3B shows a schematic cross-sectional view of the
arrangement along the axis 91 as shown in FIG. 3A. Furthermore, as
shown in FIG. 3B, the first partial opening 3101 and the second
partial opening 3201 are filled with the solder material 400.
[0035] FIG. 3C shows a schematic cross-sectional view of the
arrangement along the axis 91 as shown in FIG. 3A. Furthermore, as
shown in FIG. 3C, a portion of the solder material 400 has been
ejected from the first partial opening 3101 to provide solder
material 400 for a projecting solder contact 601. The first partial
opening 3101 may act as a reservoir for holding solder material 400
during a prior process stage, as shown in FIG. 3B, which may
subsequently be ejected from the first partial opening 3101, as
shown in FIG. 3C, to form the solder contact 601. In one
embodiment, the round shape of the second field 3102 and the
metallization pad 501 may provide a round or circular cross-section
of the solder contact 601, which may, in turn, provide a solder
ball with a regular and spherical curvature.
[0036] FIGS. 4A through 4C show a solder contact in various stages
during manufacturing according to another embodiment. FIG. 4A shows
a schematic top view of first partial openings 3102 and a second
partial opening 3202 in a structured layer 202 on the substrate
100. The first partial openings 3102 above first fields 1211 of the
substrate surface 1001 (as shown in FIGS. 4B and 4C) and the second
partial opening 3202 above a second field 1212 of the substrate
surface 1001 (as shown in FIGS. 4B and 4C) form a continuous
opening in the structured layer 202. A metallization pad 502 is
arranged on the substrate 100 in the area of the second field
1212.
[0037] In one embodiment, the first fields 1211 may comprise
rectangular shapes and the first partial openings 3102 may comprise
rectangular cross-sections. An aspect ratio of the respective
rectangular areas may be above 1, may be above 2, or may be above
5. The length of the respective rectangular areas may be in a range
of 1 to 10 microns, may be in a range of 10 to 100 microns, or may
be in a range of 100 to 1000 microns. The arrangement of the first
partial openings 3102 may be such that they extend radially from
the second partial opening 3202. The second field 1212 may comprise
a round shape and the second partial opening 3202 may comprise a
round cross-section. A median diameter of the respective round area
may be in a range of 1 to 10 microns, may be in a range of 10 to
100 microns, or may be in a range of 100 to 100 microns.
[0038] FIG. 4B shows a schematic cross-sectional view of the
arrangement along the axis 92 as shown in FIG. 4A. Furthermore, as
shown in FIG. 4B, the first partial openings 3102 and the second
partial opening 3202 are filled with the solder material 400.
[0039] FIG. 4C shows a schematic cross-sectional view of the
arrangement along the axis 92 as shown in FIG. 4A. Furthermore, as
shown in FIG. 4C, a portion of the solder material 400 has been
ejected from the first partial openings 3102 to provide solder
material 400 for a projecting solder contact 602. The first partial
openings 3102 may act as a reservoir for holding solder material
400 which may subsequently be ejected to form the solder contact
602. In one embodiment, a plurality of reservoirs may hold solder
material 400 for the solder contact 602, which may provide an
increased volume, size, diameter, and/or projection. Furthermore,
the radial arrangement of the reservoirs as the first partial
openings 3102 may influence the shape of the solder contact 602 and
may provide an improved spherical curvature thereof.
[0040] FIGS. 5A through 5C show a solder contact in various stages
during manufacturing according to another embodiment. FIG. 5A shows
a schematic top view of a first partial opening 3103 and a second
partial opening 3203 in a structured layer 203 on the substrate
100. The first partial opening 3103 above a first field 1311 of the
substrate surface 1001 (as shown in FIGS. 5B and 5C) and the second
partial opening 3203 above a second field 1312 of the substrate
surface 1001 (as shown in FIGS. 5B and 5C) form a continuous
opening in the structured layer 203. A metallization pad 503 may be
arranged on the substrate 100 in the area of the second field
1312.
[0041] In one embodiment, the first field 1311 may comprise a
rectangular shape and the first partial opening 3103 may comprise a
rectangular cross-section. The aspect ratio and the length of the
respective rectangular area may be such as being described in
conjunction with embodiments described herein. Furthermore, the
second field 1312 may comprise a rectangular or square shape and
the second partial opening 3203 may comprise a rectangular or
square cross-section. An aspect ratio of the respective rectangular
or square areas may be above 1, may be above 2, or may be above 5.
The length of the respective rectangular or square areas may be in
a range of 1 to 10 microns, may be in a range of 10 to 100 microns,
or may be in a range of 100 to 1000 microns. Nevertheless, the
shape or cross-section of the metallization pad 503 may be round
and such to fit into the second field 1312. The arrangement of the
first partial opening 3103 may be such that it is orienteered
toward a corner or an edge of the second partial opening 3203.
[0042] FIG. 5B shows a schematic cross-sectional view of the
arrangement along the axis 93 as shown in FIG. 5A. Furthermore, as
shown in FIG. 5B, the first partial opening 3103 and the second
partial opening 3203 are filled with the solder material 400.
[0043] FIG. 5C shows a schematic cross-sectional view of the
arrangement along the axis 93 as shown in FIG. 5A. Furthermore, as
shown in FIG. 5C, a portion of the solder material 400 has been
ejected from the first partial openings 3103 to provide solder
material 400 for a projecting solder contact 603. In one
embodiment, the interface between the first partial opening 3103
and the second partial opening 3203 at a corner or an edge of the
second partial opening 3203 may provide an improved channel for the
solder material 400 when leaving the first partial opening 3103 and
forming the solder contact 603. In addition to this, a round shape
of the metallization pad 503 in conjunction with a rectangular
shape of the second field 1312 may improve the formation of the
solder contact 603.
[0044] FIGS. 6A through 6C show a solder contact in various stages
during manufacturing according to another embodiment. FIG. 6A shows
a schematic top view of first partial openings 3104 and a second
partial opening 3204 in a structured layer 204 on the substrate
100. The first partial openings 3104 above first fields 1411 of the
substrate surface 1001 (as shown in FIGS. 6B and 6C) and the second
partial opening 3204 above a second field 1412 of the substrate
surface 1001 (as shown in FIGS. 6B and 6C) form a continuous
opening in the structured layer 204. A metallization pad 504 is
arranged on the substrate 100 in the area of the second field
1412.
[0045] In one embodiment, the first fields 1411 may comprise
rectangular shapes and the first partial openings 3104 may comprise
rectangular cross-sections. Furthermore, the second field 1412 may
comprise a rectangular or square shape and the second partial
opening 3204 may comprise a rectangular or square cross-section.
The aspect ratio and the length of the respective rectangular or
square areas be such as being described in conjunction with
embodiments described herein. Nevertheless, the shape or
cross-section of the metallization pad 504 may be round and such to
fit into the second field 1412. The arrangement of the first
partial openings 3104 may be such that they are orienteered toward
a side face of the second partial opening 3204.
[0046] FIG. 6B shows a schematic cross-sectional view of the
arrangement along the axis 94 as shown in FIG. 6A. Furthermore, as
shown in FIG. 6B, the first partial openings 3104 and the second
partial opening 3204 are filled with the solder material 400.
[0047] FIG. 6C shows a schematic cross-sectional view of the
arrangement along the axis 94 as shown in FIG. 6A. Furthermore, as
shown in FIG. 6C, a portion of the solder material 400 has been
ejected from the first partial openings 3104 to provide solder
material 400 for a projecting solder contact 604. In one
embodiment, the plurality of reservoirs may hold solder material
400 for the solder contact 604, which may be increased in volume,
size, diameter, and/or projection. Furthermore, the radial
arrangement the reservoirs as the first partial openings 3104 and
the inlets at side faces of the second partial opening 3204 may
influence the shape of the solder contact 604 and may provide an
improved spherical curvature thereof. In addition to this, a round
shape of the metallization pad 504 in conjunction with a
rectangular shape of the second field 1412 may improve the
formation of the solder contact 604.
[0048] FIGS. 7A through 7C show a solder contact in various stages
during manufacturing according to another embodiment. FIG. 7A shows
a schematic top view of a first partial opening 3105 and a second
partial opening 3205 in a structured layer 205 on the substrate
100. The first partial opening 3105 above a first field 1511 of the
substrate surface 1001 (as shown in FIGS. 7B and 7C) and the second
partial opening 3205 above a second field 1512 of the substrate
surface 1001 (as shown in FIGS. 7B and 7C) form a continuous
opening in the structured layer 205. A metallization pad 505 may be
arranged on the substrate 100 in the area of the second field
1512.
[0049] In one embodiment, the first field 1511 may comprise a
rectangular shape and the first partial opening 3105 may comprise a
rectangular cross-section. Furthermore, the second field 1512 may
comprise a rectangular or square shape and the second partial
opening 3205 may comprise a rectangular or square cross-section.
The aspect ratio and the length of the respective rectangular or
square areas be such as being described in conjunction with
embodiments described herein. Nevertheless, the shape or
cross-section of the metallization pad 505 may be round and such to
fit into the second field 1512. The arrangement of the first
partial opening 3105 may be such that it is orienteered at a corner
or an edge of the second partial opening 3205 and may be arranged
perpendicular to one face of the second partial opening 3205.
[0050] FIG. 7B shows a schematic cross-sectional view of the
arrangement along the axis 95 as shown in FIG. 7A. Furthermore, as
shown in FIG. 7B, the first partial opening 3105 and the second
partial opening 3205 are filled with the solder material 400.
[0051] FIG. 7C shows a schematic cross-sectional view of the
arrangement along the axis 95 as shown in FIG. 7A. Furthermore, as
shown in FIG. 7C, a portion of the solder material 400 has been
ejected from the first partial openings 3105 to provide solder
material 400 for a projecting solder contact 605. In one
embodiment, the interface of the first partial opening 3105 and the
second partial opening 3205 at a corner of the opening 3205 may
provide an improved channel for the solder material 400 when
leaving the first partial opening 3105 and forming the solder
contact 605. An injection of liquid solder material into the second
partial opening 3205 from the first partial opening 3105 at a
corner may provide a spin to the liquid material, which, in turn,
may improve a spherical geometry of a solder ball being formed by
the solder contact 605. In addition to this, a round shape of the
metallization pad 505 in conjunction with a rectangular shape of
the second field 1512 may improve the formation of the solder
contact 605.
[0052] FIGS. 8A through 8C show a solder contact in various stages
during manufacturing according to another embodiment. FIG. 8A shows
a schematic top view of a first partial opening 3106 and a second
partial opening 3206 in a structured layer 206 on the substrate
100. The first partial opening 3106 above a first field 1611 of the
substrate surface 1001 (as shown in FIGS. 8B and 8C) and the second
partial opening 3206 above a second field 1612 of the substrate
surface 1001 (as shown in FIGS. 8B and 8C) form a continuous
opening in the structured layer 206 and may be connected by a
channel 3306 in the structured layer 206. A metallization pad 506
is arranged on the substrate 100 in the area of the second field
1612.
[0053] In one embodiment, the first field 1611 surrounds the second
field 1612. Both the first field 1611 and the second field 1612 may
comprise a rectangular, a round, a hexagonal, or a polygonal shape.
The aspect ratio and the length of a side face of the respective
areas may be such as being described in conjunction with
embodiments described herein. Nevertheless, the shape or
cross-section of the metallization pad 506 may be round and such to
fit into the second field 1612.
[0054] FIG. 8B shows a schematic cross-sectional view of the
arrangement along the axis 96 as shown in FIG. 8A. Furthermore, as
shown in FIG. 8B, the first partial opening 3106 and the second
partial opening 3206 are filled with the solder material 400.
[0055] FIG. 8C shows a schematic cross-sectional view of the
arrangement along the axis 96 as shown in FIG. 8A. Furthermore, as
shown in FIG. 8C, a portion of the solder material 400 has been
ejected from the first partial opening 3106 to provide solder
material 400 for a projecting solder contact 606. In one
embodiment, a first partial opening 3106 which surrounds the second
partial opening 3206 may provide an increased volume and thereby
may provide more solder material 400 to the solder contact 606.
Furthermore, the increased length along a circumference of the
surrounding opening, in respect to a reduced width of the first
partial opening 3106, may provide improved properties during
ejection by means of surface tension forces (which may cause the
solder to be pulled from the first field), while still providing a
sufficient or even increased reservoir volume for holding solder
material 400.
[0056] FIG. 9 shows a schematic side view of an integrated circuit
according to another embodiment. An integrated circuit 30 comprises
the substrate 100 and a structured layer 207 on the substrate
surface 1001 of the substrate 100. In one embodiment, the
structured layer 207 may comprise a discontinuous layer, hence
comprising trenches 2070 and islands 2071 of the structured layer
207. In one embodiment, the discontinuous structured layer 207 may
allow for subsequent molding- and/or underfill-processes. During
such processes, the trenches 2070 may be filled with a package
mold, a resin, a passivating material, and/or other related
materials.
[0057] An island 2071 of the structured layer 207 may comprise an
opening from which partially solder material 400 has been expelled
to form solder contacts 507, which may comprise and/or provide the
topography of a solder ball. Within the trenches 2070 of the
structured layer 207, the material of the substrate 100 and/or the
substrate surface 1001 may be accessible. The openings of the
structured layer 207 may be such as described in conjunction with
embodiments described herein. Furthermore, the substrate surface
1001 may comprise first and second fields, and/or metallization
pads as described in conjunction with embodiments described
herein.
[0058] FIG. 10 shows a schematic side view of an integrated circuit
according to another embodiment. An integrated circuit 40 comprises
the substrate 100 and a structured layer 208 on the substrate
surface 1001 of the substrate 100. In one embodiment, the
structured layer 208 provides a continuous structured layer. On the
continuous structured layer 208 there may be arranged solder
contacts 508, which comprise a solder material 400 which has been
expelled from an opening of the structured layer 208. The openings
of the structured layer 208 may be such as described in conjunction
with embodiments described herein. Furthermore, the substrate
surface 1001 may comprise first and second fields, and/or
metallization pads as described in conjunction with embodiments
described herein.
[0059] FIGS. 11A through 11F show schematic views of a solder
contact being formed on a substrate, in various stages during
manufacturing, according to another embodiment. As shown in FIG.
11A, a structured layer 209 may comprise an opening 3900 with an
aperture 3901 at a layer surface 2001 of the structured layer 209.
The opening 3900 may comprise any of the first partial openings and
second partial openings, as they have been described in conjunction
with embodiments described herein. On the substrate surface 1001 of
the substrate 100 there is arranged a metallization pad 509 in the
area of a second field. Nevertheless, the metallization pad 500 may
be omitted, in the case that the material in the area of a second
field provides wetting to a solder material. An integrated circuit
50 comprises the substrate 100 and the structured layer 209.
[0060] As shown in FIG. 11B, the integrated circuit 50, comprising
the arrangement of the substrate 100 and the structured layer 209,
may be arranged such that the aperture 3901 of the opening 3900 is
facing downward. In the opening 3900 a first pressure is provided.
This first pressure may be a vacuum pressure, a low atmospheric
pressure, atmospheric pressure, a pressure below 10 mbar, a
pressure below 1 mbar, or a pressure below 10.sup.-1 mbar. The
first pressure may be provided by placing the integrated circuit 50
into a recipient, in which a controlled atmosphere and/or vacuum
may be provided by means of pumps and/or respective pressure
gauges.
[0061] As shown in FIG. 11C, a bath 4000 of a liquid solder
material 401 is provided to the aperture 3901 of the opening 3900.
This may be effected, as shown, by dipping the integrated circuit
50 into the bath 4000. The liquid solder material 401 may be or
comprise a solder material 401 in a liquid state and/or above a
melting temperature of the solder material 401.
[0062] Furthermore, the liquid material 401 may be provided to the
aperture 3901 of the opening 3900, for example, by placing the
liquid material 401 on the structured layer 209, or covering the
structured layer 209 with the liquid solder material 401. In this
case, the arrangement of the substrate 100 and the structured layer
209 may be handled and left such as shown in FIG. 11A, i.e., the
up-side-down flipping of the integrated circuit 50, as shown in
FIG. 11B, may be omitted. Nevertheless, the first pressure is
provided in the opening 3900 prior to the covering of the
structured layer 209.
[0063] As shown in FIG. 11D, a second pressure is provided, acting
onto the bath 4000 of the liquid solder material 401. In one
embodiment, the second pressure is greater than the first pressure.
The second pressure may be atmospheric pressure, high atmospheric
pressure, in a range between 700 mbar and 1.3 bar, in a range of
1.3 bar and 3.0 bar, or in a range of 3.0 bar and 10.0 bar. By
means of providing a second pressure, acting on the bath 4000,
which is greater than the first pressure, liquid material 401 may
be pressed into the opening 3900 (as shown in FIGS. 11A-11C),
thereby filling the opening 3900 (as shown in FIGS. 11A-11C) with
the liquid solder material 401.
[0064] As shown in FIG. 11E, the integrated circuit 50 may be
extracted from the bath 4000, and the opening 3900 remains filled,
after solidification, with the solid solder material 400. Such a
solidification may be effected by a cooling of the integrated
circuit 50 with a well-defined and pre-determined temperature
profile. A temperature profile comprises the controlled setting of
the temperature of the integrated circuit 50 in respect to
time.
[0065] Furthermore, in one embodiment, an oxide-layer on the solder
material 400 in an area of the aperture 3901 (as shown in FIGS.
11A-11C) may be removed. Such an oxide may be formed on the solder
material 400, when exposed to air, oxygen, or atmospheric
conditions. The removal may be effected by an exposure of the
oxide, a filled structured layer 209, or the integrated circuit 50
to a hydrogen-plasma, formic acid, forming gas, a combination of
hydrogen and nitrogen, a flux, collophony, urea, zinc chloride,
and/or related chemicals and gases. The removal of an oxide may be
carried out prior to a reflow soldering process, or, in general,
prior or during the ejection of the solder material from the
opening.
[0066] As shown in FIG. 11F, a solder contact 609 is formed on the
surface of the structured layer 209. This may be effected by means
of expelling a portion of the solder material 400 from the opening
3900 (as shown in FIGS. 11A-11C), by means of a further heating and
or liquefaction of the solder material 400. Whereas the solder
material 400 is kept in place above the metallization pad 509,
solder material 400 is expelled from the opening 3900 when the
facing material and/or surface impedes wetting to the solder
material 400. An expulsion of the respective solder material 400
may be effected by means of surface tension acting on a liquefied
solder material 400 within the opening 3900.
[0067] Such an expelling may include the transfer of solder
material 400 from a partial opening of the opening 3900, acting as
a reservoir, to solder contact 609. Such an expulsion, heating, or
liquefaction may be conducted in a vacuum, in a vacuum below 10
mbar, in a vacuum below 1 mbar, or in a vacuum below 10.sup.-1
mbar.
[0068] The solder contact 609 may provide a solder ball being
arranged on the surface of the structured layer 209. Such a solder
ball may provide a geometry of a copper pillar or other related
studs, stud bumps, or solder balls. Furthermore, the structured
layer 209 may remain on the substrate 100 after formation of the
solder contact 609, which may ease fabrication and/or reduce
process complexity. By means of designing the shape and size of the
opening 3900, in conjunction with the size, shape and position of
the metallization pad 504, the volume, size, diameter, height,
and/or projection of the solder contact 609 may be controlled.
[0069] FIGS. 12A and 12B show schematic views of an integrated
circuit in conjunction with a circuit board according to another
embodiment. As shown in FIG. 12A, an integrated circuit 60 may
comprise the substrate 100, a structured layer 210, and solder
contacts 610. The integrated circuit 60 in this state may have been
provided according to embodiments described herein. The solder
contacts 610 may have been formed by a method which has been
described in conjunction with embodiments described herein.
Furthermore, the solder contacts 610 may have been formed by the
expulsion of a solder material from a partial opening in the
structured layer 210, whereas the solder contacts 610 are coupled
to metallization pads which are arranged on the substrate surface
1001 of the substrate 100.
[0070] In one embodiment, the integrated circuit 60 may be
connected to a circuit board 800 with contact pads 700. The circuit
board 800 may comprise a module board, a printed circuit board
(PCB), a motherboard, a module-in-package (MIP) board, a
multi-module package (MMP) board, a carrier substrate, a chip
carrier, and/or any other entity which may connect the integrated
circuit 60 to an external circuitry, or may itself comprise a
further integrated or external circuit. Furthermore, the integrated
circuit 60 in conjunction with the circuit board 800 may form or
comprise a flip-chip in package (FCiP) or a fine pitch flip-chip on
chip (FCoC). In the latter case, the circuit board 800 may itself
be or comprise a further substrate or a stack thereof. The contact
pads 700 may be arranged on the circuit board 800 at the respective
positions which match the positions of the solder contacts 610.
Furthermore, the material and/or the surface of the contact pads
700 may provide a wetting to a solder material 400 of the solder
contacts 610.
[0071] As shown in FIG. 12B, the arrangement of the substrate 100
and the structured layer 210 may be soldered to the circuit board
800. This may be effected by placing the integrated circuit 60 in
the vicinity of the circuit board 800, such that the solder
contacts 610 are brought into a close vicinity of the respective
contact pads 700 or are brought into mechanical contact with the
contact pads 700. A soldering process, such as a reflow soldering
process, an infrared soldering process, or an ultrasonic soldering
process, may liquefy the solder contacts 610 and promote, in this
way, a soldering to the contact pads 700. After solidification, the
solder balls 610 may form solid solder contacts 610 to the contact
pads 700. Such soldering process may be conducted in a vacuum, in a
vacuum below 10 mbar, in a vacuum below 1 mbar, or in a vacuum
below 10.sup.-1 mbar.
[0072] FIGS. 13A and 13B show schematic views of an integrated
circuit in conjunction with a circuit board according to another
embodiment. As shown in FIG. 13A, an integrated circuit 70
comprises the substrate 100, a structured layer 211. The structured
layer may comprise openings being filled with a solder material.
The openings, the solder material, and the filling thereof may be
according to an implementation as described in conjunction with
embodiments described herein. The integrated circuit 70 is to be
connected to the circuit board 800 with contact pads 700, which has
been described in conjunction with FIG. 12A.
[0073] As shown in FIG. 13B, the integrated circuit 70 is soldered
to the circuit board 800. This may be effected by placing the
integrated circuit 70 in the vicinity of the circuit board 800 and
a subsequent soldering process. Such a solder process liquefies the
solder material in the openings of the structured layer 211,
thereby ejecting a portion thereof. The portion of the solder
material may establish a mechanical contact to the contact pads 700
through ejection and may be soldered to the material and/or the
surface of the contact pads 700. Hence, In one embodiment, the
solder material 400 may remain in the openings of the structured
layer 211. In this way, a portion of the solder material 400 may be
expelled from the openings of the structured layer 211 and may form
a solder contact 611 to the facing contact pads 700 on the circuit
board 800. Furthermore, the integrated circuit 60 in conjunction
with the circuit board 800 may form or comprise a flip-chip in
package (FCiP) or a fine pitch flip-chip on chip (FCoC). In the
latter case, the circuit board 800 may itself be or comprise a
further substrate or a stack thereof.
[0074] FIG. 14 shows a schematic top view of a portion of an
integrated circuit according to yet another embodiment.
Accordingly, an integrated circuit 80 may comprise the substrate
100 and a structured layer 212, which may comprise islands 2120 of
the structured layer 212. The islands 2120 comprise a first partial
opening 3112 and a second partial opening 3212. The first partial
opening 3112 may be arranged on the substrate 100 such that the
surface of the substrate is exposed, whereas a metallization pad
512 is arranged in the area of the second opening 3212. The surface
and/or the material of the metallization pad 512 may provide a
wetting to a solder material, whereas the surface and/or the
material of the surface of the substrate or the substrate 100
impedes the wetting by a solder material. The openings, comprising
the first partial opening 3212 and the second partial opening 3212,
may be filled with a solder material, which, in a subsequent
process stage, may be partially expelled in order to form a solder
contact.
[0075] In one embodiment, the islands 2120 may be arranged in a
regular array. Accordingly, the array of the solder contacts may
provide a plurality of solder contacts and contacts to an
integrated circuit in parallel.
[0076] According to another embodiment, the opening may be filled
with a liquid solder material, a liquefied solder material, a
granular solder material, a powder-like solder material, and/or a
paste-like solder material. In this way, process temperatures
during filling the openings with the solder material may be reduced
and an overall thermal budget may be decreased. Furthermore, a
combination of a solder material and a flux material, for example
in form of a granular solder material in a flux matrix or in form
of a solder paste, may be applied to the opening in a single
process stage.
[0077] The preceding description only describes advantageous
exemplary implementations of the invention. The features disclosed
therein and the claims and the drawings can, therefore, be
important for the realization of the invention in its various
implementations, both individually and in combination. While the
foregoing is directed to implementations of the present invention,
other and further implementations of this invention may be devised
without departing from the basic scope of the invention. The scope
of the present invention being determined by the claims as
follows.
* * * * *